Multimode land mobile radio

ABSTRACT

A multimode land mobile radio (LMR) and a method of communicating land mobile radio (LMR) content using an LMR device are provided. The LMR includes an LMR communication portion configured to provide communication with an LMR network and a cellular data network communication portion configured to provide communication with a cellular data network.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of and claims priority tocopending non-provisional U.S. patent application entitled “SystemProviding Land Mobile Radio Content Using a Cellular Data Network,”assigned Ser. No. 11/130,975, and filed May 17, 2005, which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

This invention relates generally to land mobile radios, and moreparticularly, to a land mobile radio providing communication of landmobile radio content using a land mobile radio network or a cellulardata network.

Land mobile radios (LMRs) may be used to provide communication betweendifferent mobile units. Land mobile radio band communication, forexample, public safety radio communication (e.g., police, firedepartment, etc.) is generally available within the VHF, UHF, 700 MHzand 800 MHz frequency bands. Part of each of these frequency bands isallocated by the Federal Communications Commission (FCC) for publicsafety communication services and are also referred to as Public SafetyFrequency Bands. These communications also may be provided using privateland mobile radio services (PLMRS).

Cellular networks also provide communication between different mobileusers, for example, cellular telephones. These cellular networks, aswell as LMR networks, continue to be enhanced and allow for improvedoperation and communication. For example, cellular networks now providePush-to-talk (PTT) services that allow direct connect capabilities.Thus, a cellular phone user may request a direct connect communicationlink with another cellular phone user in a two way radio or “walkietalkie” type communication. As another example, cellular networksprovide high-speed data services, such as, for example, General PacketRadio Service (GPRS), Enhanced Data Rates for GSM Evolution (EDGE),Evolution Data Optimized (EV-DO) and Universal Mobile Telephone Service(UMTS).

Known systems providing enhanced services or features, such as enhancedcalling or voice features, which may be used, for example, for missioncritical wireless applications, such as public safety applications, usecommercial cellular services, such as PTT services, to augment and orreplace traditional LMR systems. These known systems are provided usingspecialized gateway equipment that enable certain interoperabilitycapabilities between an LMR system and a cellular network with, forexample, PTT capabilities. The interoperability is provided bytranslating and/or transforming the data or voice communications to becommunicated between the networks, for example, from an LMR network to acellular network.

In the LMR area, new technologies are also being provided, including theuse of digital communication instead of analog communication.Additionally, LMR systems are now using packet switching instead ofcircuit switching, for example, using Internet Protocol (IP) and VoiceOver IP (VoIP) to enable construction of highly scalable and costeffective LMR networks.

However, these improvements also result in need to support migration tonew technologies. Further, interoperability between systems deployedeither by different LMR owners/operators or between different cellularcarriers, particularly when different technologies are used in differentsystems, is increasingly important. It is known to utilize multimodeterminal devices to facilitate both migration and interoperability. InLMR, these devices are often referred to as multimode radios, and in thecellular area these devices are often referred to as multimode phones.

Multimode terminal devices enable inter-system roaming, andspecifically, roaming from one network and/or technology to another,without user intervention. These terminal devices change mode as a userroams between different systems provided using different technologies.Further, components for operation in multiple protocols and frequencybands may be integrated into a single terminal device. For example, inthe cellular area, multimode phones can roam between TDMA and CDMAnetworks. In the LMR are, radios can roam between an analog trunkedsystem and a digital trunked system.

Multimode operation is provided by the interconnection of correspondingnetwork infrastructures. Thus, to provide transparency to a user,gateway equipment may be used to connect the various systems ornetworks. Known devices for communicating between different types ofnetworks or systems use different communication components (e.g.,hardware and software) each configured specifically to communicate witha particular network or system. For each system or network, thefunctions and operations for that system or network are implementedusing the capabilities and protocols specific to that system or network.However, these systems are limited in the set of overall functions thatare available because the functions and user interface available to auser depend on the system into which the terminal device has roamed.

Further, the functions of one system may differ significantly from thefunctions available on another system. Additionally, because of theseprotocol incompatibilities certain end-to-end services cannot beprovided, for example, end-to-end encryption. For voice communications,the use of a gateway to interconnect systems can introduce degradationin voice quality as a result of the voice data being converted from oneformat to another.

Thus, these systems not only may operate at non-satisfactory qualitylevels, but may require additional controls and equipment to implementthe interconnectivity, thereby adding complexity and cost to the overallsystems.

BRIEF DESCRIPTION OF THE INVENTION

In one exemplary embodiment, a land mobile radio (LMR) is provided thatincludes an LMR communication portion configured to providecommunication with an LMR network and a cellular data networkcommunication portion configured to provide communication with acellular data network.

In another exemplary embodiment, a multimode terminal device is providedthat includes a land mobile radio and a cellular radio modem.

In yet another exemplary embodiment, a method of communicating landmobile radio (LMR) content using an LMR device is provided. The methodincludes configuring a land mobile radio to communicate LMR contentusing one of an LMR network and a cellular data network. The LMR contentis encapsulated using a packet switching protocol when communicatingusing the cellular data network.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a Land Mobile Radio (LMR) communicationsystem constructed in accordance with an exemplary embodiment of thepresent invention.

FIG. 2 is a block diagram of an LMR unit constructed in accordance withan exemplary embodiment of the present invention.

FIG. 3 is a block diagram illustrating an internal configuration of anLMR unit constructed in accordance with an exemplary embodiment of thepresent invention.

FIG. 4 is a perspective view of an LMR unit illustrating an externalconfiguration constructed in accordance with an exemplary embodiment ofthe present invention.

FIG. 5 is a perspective view of an LMR unit illustrating an externalconfiguration constructed in accordance with another exemplaryembodiment of the present invention.

FIG. 6 is a perspective view of an LMR unit illustrating an externalconfiguration constructed in accordance with another exemplaryembodiment of the present invention.

FIG. 7 is an elevation view of an LMR unit illustrating an externalconfiguration constructed in accordance with another exemplaryembodiment of the present invention.

FIG. 8 is a block diagram illustrating protocol stacks in accordancewith an exemplary embodiment of the present invention.

FIG. 9 is a flowchart of a method for controlling communication of LMRcontent in an LMR communication system in accordance with an exemplaryembodiment of the present invention.

FIG. 10 is a block diagram of a packet switched protocol interfaceconstructed in accordance with an exemplary embodiment of the presentinvention.

FIG. 11 is a block diagram showing formatted LMR content in accordancewith an exemplary embodiment of the present invention.

FIG. 12 is flowchart of a method for selecting the operating mode of anLMR unit in accordance with an exemplary embodiment of the presentinvention.

FIG. 13 is a flowchart of a method for processing LMR content inaccordance with an exemplary embodiment of the present invention.

FIG. 14 is a block diagram of an LMR communication system constructed inaccordance with an exemplary embodiment of the present invention showingcommunication coverage areas.

FIG. 15 is block diagram of an LMR communication system constructed inaccordance with an exemplary embodiment of the present invention showingdata flow.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the present invention include a multimodeterminal device having a land mobile radio (LMR) unit providing LMRcontent, for example, LMR services using both an LMR network and acellular data network. The LMR content retains an LMR application layer,but instead of using the LMR frequency bands with LMR transportprotocols, the LMR content is communicated using cellular frequencybands over cellular packet switched data networks.

The multimode device is configured to provide inter-system roamingbetween, for example, LMR systems and cellular systems. Operation usingthe cellular system is provided generally by including a cellular radiomodem into an LMR device, and supporting LMR features throughencapsulation and transport of LMR voice, data and control information,utilizing end-to-end packet switched protocols between the LMR deviceand a packet switched infrastructure.

In the various embodiments, the data services of a cellular system areused when communicating using the cellular system. The cellular radiomodem provides data services between an application layer within the LMRdevice and a gateway that bridges the LMR system or network and thecellular system or network. The end-to-end protocols between themultimode LMR device and the gateway utilize encapsulation techniques totransport LMR voice and data services over the cellular data network.The processes and techniques for performing the encapsulation and packetswitched transport also may be referred to as LMR-over-cellularprotocols.

It should be noted that when reference is made herein to LMR content,this refers generally to any type or kind of LMR voice and/or datacontent, and may define particular LMR services, operations, controls,etc. For example, the LMR content may include, but is not limited to,voice data, emergency signal data, control data relating to selecting aparticular talk group, LMR data for transfer between a radio unit and aserver, reprogramming data (e.g., software upgrade data), etc.

A wireless communication system will first be described followed by adescription of an LMR unit in accordance with various embodiments of theinvention.

As shown in FIG. 1, a wireless communication system, and moreparticularly, an LMR communication system 20 constructed according tovarious embodiments of the invention provides communication between aplurality of multimode devices, and more particularly, a plurality ofLMR units 22 or LMR terminals. Communication between the LMR units 22 isprovided via either an LMR network 24 or a cellular data network 26.Each of the LMR units 22 is configured to provide communication, forexample, with other LMR units 22 using one of the LMR network 24 and thecellular data network 26. In particular, each of the LMR units 22 isconfigured to switch between one of the LMR network 24 and the cellulardata network 26, for example, based on the available network, availablebandwidth, the coverage area, the communication signal strength, etc.Optionally, or in another embodiment, switching between one of the LMRnetwork 24 and the cellular data network 26 is based on the type ofcommunication or content. Thus, in addition to providing communicationover the LMR network 24, wireless data services of the cellular datanetwork 26 may be used to support the communication and/or transport ofLMR application layer protocols.

Various embodiments of the present invention enable end-to-end LMRservices to be overlaid on top of the cellular data network 26, therebyallowing, for example, implementation of mission critical LMR systemswithin the service area of these cellular data networks 26. In order toprovide this functionality and communication of LMR content using thecellular data network 26, each of the LMR units 22, for example, LMRradios, is provided with a cellular radio modem to allow operatingend-to-end LMR application layer protocols and services between the LMRunits 22 and the packet switched LMR infrastructure.

More particularly, and as shown in FIG. 2, a multimode terminal device,illustrated as the LMR unit 22, includes a plurality of modules orcomponents configured to provide communication via the LMR network 24 orthe cellular data network 26. Specifically, the LMR unit 22 includes anLMR application module 30 connected to an LMR transport module 32 forconfiguring voice and/or data for communication via the LMR network 24(having one or more LMR base stations 46) using an LMRtransmitter/receiver 34, which may be separate units or provided as asingle transceiver (e.g., an LMR radio). The LMR application module 30,LMR transport module 32 and LMR transmitter/receiver 34 generally definean LMR communication portion 40 of the LMR unit 22. The LMR unit 22further includes an LMR encapsulation module 36 for encapsulating thevoice and/or data for communication via the cellular data network 26using a cellular radio modem 38. The LMR application module 30, LMRencapsulation module 36 and cellular radio modem 38 generally define acellular data network communication portion 42 of the LMR unit 22.

Specifically, and as shown in FIG. 3, the LMR unit 22 includes the LMRcommunication portion 40 and the cellular data network communicationportion 42 each connected to a selector 43. The LMR communicationportion 40, cellular data network communication portion 42 and selector43 are each also connected to a processor 45. Further, a memory 47(e.g., RAM and/or ROM) and a display 246 are each connected to theprocessor 45. An input/output 51 is connected to the processor 45 andthe selector 43. A user interface 250 is connected to the processor 45.

In operation, and as described in more detail herein, the processor 45is configured to control selection of either the LMR communicationportion 40 or cellular data network communication portion 42 using theselector 43. The processor 43 may access the memory 47 to obtain, forexample, user preferences or predefined operating parameters. Theprocessor 47 also may receive inputs (e.g., commands) from a user viathe user interface 250, for example, to activate or select a certainfunction or operation. The input/output 51 may include differenttransmission and/or receiving components for transmitting and receivingto and from the LMR network 24 or the cellular data network 26 (shown inFIG. 2). The display 246 displays information from the processor 45, forexample, communication information, such as channel or network selectioninformation.

Additional or different components may be provided to the LMR unit 22.For example, a global positioning system (GPS) unit may be provided aspart of the LMR unit 22 to determine the location of the LMR unit 22.

The LMR unit 22 may be configured having different externalconfigurations, for example, based on the specific application for theLMR unit 22. Various embodiments of different external configurationsfor LMR units are illustrated in FIGS. 4 through 7. It should be notedthat the internal configuration for each of the LMR units is the same orsimilar to the configuration shown in FIGS. 2 and 3. Modifications maybe made, for example, to the size of the memory 47 or display 246, orthe configuration of the user interface 250. More particularly, and forillustrative purposes, as shown in FIG. 4, an LMR unit 220 may beprovided as a portable or mobile unit having a housing 222 configuredfor handheld operation. The LMR unit 220 includes a power/volume knob224 on a top portion 228 of the LMR unit 220 to turn power on and offand to control volume. A system or channel knob 226 on the top portion228 of the LMR unit 220 is provided to, for example, change channels ortalk groups within a particular network (e.g., LMR network 24 orcellular data network 26) and may have a predetermined number of rotarypositions. An emergency button 230 and a selector knob 232 are alsoprovided on the top portion 228. The emergency button 230 is used totransmit an emergency signal to other LMR units, which provides an alertto the other units. The selector knob 232 is used to select a bank orset of channels or talk groups. An antenna 234 extends from the topportion 228 to facilitate bi-directional communication with the LMR unit220.

A side portion 236 of the LMR unit 220 also includes control members forcontrolling operation of the LMR unit 220. In this embodiment, an optionbutton 238, a clear/monitor button 240 and a push-to-talk (PTT) button242 are all provided on the side portion 236. The option button 238 isused to select different options, for example, within a particularoperating mode (e.g., high/low power settings, keypad lock, displaycontrast, keypad lighting, etc.) and the clear/monitor button is used,for example, to clear a setting or end a call. The PTT button 244 isused to activate and deactivate PTT operations.

A front portion 244 of the LMR unit 220 generally includes the display246, a speaker 248, a microphone 259 and a user interface 250. The userinterface 250 includes a plurality of user depressible buttons that maybe used, for example, for entering numeric inputs and selecting variousfunctions of the LMR unit 220. This portion of the user interface may beconfigured, for example, as a numeric keypad. Additional control buttonsalso may be provided, for example, a menu button 252 and an increase anda decrease button 254 and 256, respectively. The increase button 252 anddecrease button 254 may be used to provide the same functions as otheruser inputs, for example, correspond to the same operations as thesystem or channel knob 226. The menu button 252 is used to access astored menu and/or activate an item within a list displayed on thedisplay 246.

With respect to the plurality of user depressible buttons correspondingto numeric inputs, each may also provide control or activation of aparticular function of the LMR unit 220. For example, numeric button (1)258 also may be used to select a specific system or network, forexample, the LMR network 24 or cellular data network 26 (shown in FIGS.1 and 2), which switches between the LMR communication portion 40 andthe cellular data network communication portion 42 (shown in FIG. 2),respectively. Numeric button (2) 260 also may be used to select aspecific group of users, for example, a predetermined group of users ona particular system. Numeric button (3) 262 also may be used to select ascan mode of operation for scanning channels within a particular systemor network. Numeric button (4) 264 also may be used to activateencryption, for example, turn on and off a private encryption mode.Numeric button (6) 266 also may be used to add a group or channel foraccessing with the LMR unit 220. Numeric button (7) 268 also may be usedto access or provide to another LMR unit status of the LMR unit 220.Numeric button (8) 270 also may be used to access a list ofpredetermined messages that can be transmitted by the LMR unit 220.Numeric button (9) 272 also may be used to delete selected groups orchannels of a currently selected system within a scan list. Button (*)274 also may be used to initiate a interconnect call with other units.Button (#) 276 also may be used to initiate an individual call.

The display 246 may be configured having a plurality of lines, forexample, for displaying a system designation on one line, a groupdesignation on another line and icons or other information (e.g., modeof operation) on additional lines. Other information may be provided onthe display 246, for example, a battery power level indicator.

The LMR unit 220 also may be referred to as a system unit. An LMR unit280 configured as a scan unit is shown in FIG. 5. Like numeralsrepresent like components as shown in FIG. 4. The user interface 250 ofthe LMR unit 280 includes only an A/D button 282 to add and deleteselected talk groups or channels from a scan list of a currentlyselected system, an SCN button 284 to turn on and off a scan operationand an OPT button 286 to activate one or more options.

Various other embodiments provide configurations of LMR units for use indifferent applications or in different settings. For example, an LMRunit 300 as shown in FIG. 6 may be configured for desktop or dashboardoperation (e.g., mounting thereon) and an LMR unit 310 as shown in FIG.7 may be integrated within a dashboard 312 of, for example, anautomobile. Like numerals in FIGS. 6 and 7 correspond to like numeralsin FIGS. 4 and 5.

The LMR units may include additional components, for example, filters(not shown), such as a receive filter and a transmit filter forfiltering signals that are received and transmitted, respectively, bythe LMR units. The LMR units also may include, for example, a dedicatedswitch (not shown) or other controller for switching between the LMRcommunication portion 40 and the cellular data network communicationportion 42 (shown in FIG. 2).

It should be noted when reference is made below to LMR unit 22, any ofthe various embodiments may be used, including LMR units 220, 280, 300and 310.

In operation, the LMR system 20 may provide communication via the LMRnetwork 24 using different known protocols, for example, LMR airlinkprotocols. For example, these LMR airlink protocols include the Project25 (TIA 102) and ETSI TETRA standards, among others. These LMR airlinkprotocols specify the format and procedures for information exchangebetween the LMR unit, for example, LMR unit 22 and the LMR network 24,and in particular, the LMR base station 46. It should be noted that whenthe base station(s) 46 are part of a larger system, the base station(s)46 are interconnected to switching equipment (not shown) that routesvoice and data between different parts of the system, such as to otherLMR base stations or dispatch consoles.

As is known, the LMR base station 46 processes, for example,manipulates, the voice, data and control information received over theairlink into an alternate format suitable for communication within theLMR network 24, for example, for transport to switching equipment. Forexample, received discrete voice, data and control transmissions may beencapsulated in TCP/IP or UDP/IP packets as is known, with the resultantIP packets communicated between the LMR base station(s) 46 and theswitching equipment over an IP network.

The LMR unit 22 also may provide communication via the cellular datanetwork 26 using different known protocols, for example, General PacketRadio Service (GPRS), Enhanced Data Rates for GSM Evolution (EDGE),Evolution Data Optimized (EV-DO), Universal Mobile Telephone Service(UMTS), and 802.16 standards, among others. These cellular protocolsspecify the format and procedures for information exchange between theLMR unit 22 and in particular, the cellular radio modem 38, and thecellular data network 26.

For example, a cellular tower (not shown) having base station (notshown) may be provided for receiving and processing signals from the LMRunit 22, for example, manipulating the received voice, data and controlinformation into an alternate format suitable for communication withinthe cellular data network 26, for example, for transport to a router andserver (not shown) based on an IP address for the data packets received.For example, received encapsulated signals are decapsulated andappropriately routed within the cellular data network 26.

Thus, communication of data from either the LMR network 24 or thecellular data network 26 to a packet switched LMR infrastructure 41 isprovided. It should be noted that the LMR content and LMR network may beconfigured based on different airlink protocols. In order to providecommunication via either the LMR network 24 or the cellular data network26 using the LMR unit 22 the communication protocol stacks forcommunication with each of these networks is partitioned as shown inFIG. 8. In particular, and with respect to communication with the LMRunit 22 using the LMR network 24, the LMR protocol stack 60 ispartitioned into multiple layers, which in an exemplary embodiment, is atwo-layer protocol stack having an LMR application layer 62 and an LMRtransport layer 64. The application layer 62 and the LMR transport layer64 may be provided, for example, by the LMR application module 30 andLMR transport module 32 (both shown in FIG. 2), respectively. The LMRapplication layer 62 is configured to provide interpretation andprocessing of the voice, data and control information and the LMRtransport layer 64 is configured to provide delivery of the voice, dataand control information over the transmission medium. As describedherein, an LMR airlink protocol defines the both the LMR applicationlayer 62 and the LMR transport layer 64.

In this two-layer protocol stack model, the LMR base station 46 (shownin FIG. 2) and switching equipment in the LMR network 24 (shown in FIG.2) receive content from the LMR communication portion 40 (shown in FIG.2) and communicate content of the LMR application layer 62 therebetweenwith a different transport layer. In particular, and as shown in FIG. 3,the content of the application layer 62 is encapsulated at the LMR basestation 46 (shown in FIG. 2) using LMR content encapsulation 66 as isknown. In an exemplary embodiment, discrete transmission units areencapsulated within transport datagrams, and in particular, packetswitched transport datagrams 68, that are communicated using a transportprotocol. Upon receipt of an encapsulated datagram, the applicationlayer content then may be recovered, and in particular, decapsulated.

Further, this two-layer protocol stack model enables delivering LMRapplication layer services over non-LMR wireless networks using, forexample, the cellular data network communication portion 42 (shown inFIG. 2). Specifically, the cellular data network communication portion42 is configured to provide the LMR application layer 62, but instead ofusing the LMR transport Layer 64, the transport services of a wirelesscellular data network 26 (shown in FIG. 2) are used. In particular, anLMR encapsulation layer 70 is used with the packet switched transportdatagrams 68 such that the wireless cellular data network 26communicates with switching equipment using suitable transportprotocols, thereby delivering the identical LMR application layerservices as the LMR communication portion 40. Specifically, the packetswitched LMR infrastructure 41 (shown in FIG. 2) communicates the LMRapplication services using LMR application layer switching 72 incombination with packet switched transport datagrams 68.

It should be noted that the various embodiments are not limited to atwo-layer protocol stack and additional layers may be provided to themulti-layer protocol stack as desired or needed. For example, differentsession layers, such as a bulk encryption layer may be provided.Further, and for example, an RTP layer may be provided.

Various embodiments of the present invention provide for controllingcommunication of LMR content in an LMR communication system using an LMRnetwork and a non-LMR wireless network, in particular, a wirelesscellular data network. In particular, a method 100 of controllingcommunication of LMR content is shown in FIG. 9 and includes determiningat 102 the network to use to communicate the LMR content. In anexemplary embodiment, a determination is made as to whether the LMRcontent is to be communicated using an LMR network or a cellular datanetwork. The determination may be based on a manual selection, forexample, based on a user input selection of which network to use. Theselection may be made, for example, using a button or switch on the LMRunit 22 (shown in FIG. 2). Alternatively or optionally, thedetermination of which network to use may be automatic. For example, theselection of a network for communicating LMR content may be based on theamount of data traffic on a particular network or available bandwidth, atransmission priority level, the type of communication or content (e.g.,voice or emergency broadcast signal, emergency communication or PTTrequest), the signal strength for the LMR unit, the geographic locationof the LMR unit, a user preference, etc. The operation and selection ofthe network to use when communicating with the LMR unit is described inmore detail below in connection with FIG. 12.

After a determination of the network to use to communicate the LMRcontent is made at 102, a method of communication is selected at 104based on the determined network to use. For example, the speed or baudrate of the communication may be selected (manually or automatically)from a range of communication data rates. Additionally, the setupprocedures for establishing and connecting to the determined network maybe selected. For example, if the LMR network is to be used, an LMRnetwork communication setup routine may be executed wherein acommunication link is established between the LMR unit and the LMRnetwork via an LMR transmitter/receiver within the LMR unit. If thecellular data network is to be used, a cellular data networkcommunication setup routine may be executed wherein a communication linkis established between the LMR unit and the cellular data network via acellular radio modem of the LMR unit. The setup routine may include anysuitable process as is known for establishing a wireless communicationlink.

Thereafter, at 106 the LMR content is configured for communication basedon the determined network and selected method of communication. Forexample, if the LMR content is to be communicated using the LMR network,a selection of a particular LMR standard in which to configure or formatthe LMR content is selected. In particular, an LMR standard in which toconfigure the voice and/or data payload defining the LMR content isselected. This may include, for example, selecting one of a Project 25(TIA 102) or an ETSI TETRA standard for the method of communication.Further, and for example, a proprietary format may be selected, forexample, an OpenSky M/A-COM proprietary format, a NetworkFirst or EDACSsystem proprietary format.

Further and for example, if the LMR content is to be communicated usingthe cellular data network, a selection of a particular wireless cellulardata network standard in which to configure or format the LMR content isselected. In particular, a wireless cellular standard in which toconfigure the voice and/or data payload defining the LMR content isselected. This may include, for example, selecting one of a GeneralPacket Radio Service (GPRS), Enhanced Data Rates for GSM Evolution(EDGE), Evolution Data Optimized (EV-DO), Universal Mobile TelephoneService (UMTS) or 802.11 system standard.

Additionally, and as described in more detail above in connection withFIG. 8, depending on the network to be used to communicate the LMRcontent, a particular protocol stack may be used. Further, if the LMRcontent is to be communicated using the LMR network, an LMR protocolheader is added to the LMR data payload. If the LMR content is to becommunicated using the cellular data network, then a packet switchprotocol header is added. As described in more detail below, if the LMRcontent is to be communicated using the cellular data network, then theLMR content is encapsulated, for example, Internet Protocol (IP)encapsulated with an IP wrapper prior to communicating to or from thecellular data network. The method for encapsulating the data isdescribed in more detail below in connection with FIG. 13.

Referring again to FIG. 9, after the LMR content is configured at 106,the configured LMR content is communicated at 108. For example, if theLMR content is configured for communication using the LMR network, anLMR transmitter and receiver may be used to communicate the LMR content.If the LMR content is configured for communication using the cellulardata network, a cellular radio modem may be used to communicate the LMRcontent. It should be noted that the cellular radio modem may beconfigured to operate in a single mode of operation or may be configuredto operate in a multiple modes. In another embodiment, more than onecellular radio modem may be provide, each of which may be configured tooperate in a single mode of operation or may be configured to operate inmultiple modes of operation.

After the LMR content is communicated and received, for example, by abase station of the network, the LMR content is processed at 110 todetermine an action. For example, this may include a determination tocommunicate voice data or to issue an emergency signal or PTT request toa talk group. For example, if the LMR content is communicated using thecellular data network, the IP destination address of an encapsulateddatagram may first be determined and then communicated to that locationfor processing using a router in the network.

Referring now to FIG. 10 and an another embodiment of the presentinvention, a packet switched protocol interface 120 may be provided inconnection with the cellular data network 26 (shown in FIG. 2). Thepacket switched protocol interface 120 may be provided, for example, asa separate unit (e.g., stand alone module), a card for connection to aserver within the cellular data network or software for downloading to aserver within the cellular data network. The packet switched protocolinterface 120 includes a processor 122 for processing received packetswitched encapsulated LMR content for communication to, for example, thepacket switched LMR infrastructure 41 (shown in FIG. 2). In particular,and as described in more detail herein, the processor may receive LMRcontent formatted as shown in FIG. 11. The LMR content generallyincludes an LMR data portion and a packet switching protocolencapsulation portion. Specifically, the LMR content 130 may include apacket switch protocol header 132, an LMR protocol header 134 and LMRdata 136, for example, an LMR data payload.

This LMR content 130 is essentially encapsulated, for example,encapsulated in an IP wrapper. The processor 122 decapsulates the LMRcontent 130, for example, by removing the packet switch protocol header132 and may store the decapsulated LMR content 130 in a memory 124. TheLMR content 130 then may be further processed by the processor 122 todetermine an action to be performed or an address within the packetswitched LMR infrastructure to which the LMR content 130 is to becommunicated. Essentially, once the LMR content 130 is decapsulated, theLMR content 130 is configured for communication within a packet switchedLMR infrastructure or an LMR network. The control of communication ofthe LMR content 130 is controlled by a controller 126 that may include arouter 128 for routing the LMR content 130 to a destination within, forexample, the LMR network. It should be noted that the LMR content may bereencapsulated for transmission within the LMR network or within thecellular data network.

The operation and selection of the network to use by the LMR unit, andmore particularly, the selection of either an LMR network or a non-LMRnetwork, for example, a cellular data network, to communicate the LMRcontent will now be described. In general, an LMR unit may automaticallyselect the network to use based on, for example, a user setting, apredetermined setting, a user defined setting, an operating condition ofthe LMR unit, etc. The system selection also may be made by a user usinga selector or input on the LMR unit. A method 350 for selecting theoperating mode of the LMR unit, and more particularly, for determiningwhen to use a particular network for communication is shown in FIG. 12.Specifically, a determination is made at 352 as to the current networkor communication system being used. Next, a determination of theoperating conditions of the LMR unit is made at 354. This may include,for example, the current signal strength, the current geographiclocation, etc. Thereafter, at 356, a determination is made as to anyuser input or preference for a particular network. For example, a usermay input a particular network preference based on geographic area, suchas a preference for using an LMR network in an area where the user knowsthat the cellular data network coverage is weak or alternatively forusing a cellular data network where the user knows there is no LMRnetwork coverage. The user preference also may be, for example, to firstalways use a cellular data network if available. The input also may bebased on a manual user selection of the LMR network or the cellular datanetwork using a button or selector on the LMR unit.

Thereafter at 358 a determination is made as to the LMR settings of theLMR unit. This may include, for example, determining preprogrammedsettings or preferences for the LMR unit, such as, for example, based onthreshold levels of data traffic on a particular network or availablebandwidth on that network, a transmission priority level, the type ofcommunication or content (e.g., voice or emergency broadcast signal,emergency communication or PTT request), the current network being usedfor communication, etc. A determination is then made at 360 as towhether the LMR settings override the user input or preference, or viceversa. For example, the LMR unit may be configured such that anemergency broadcast message must be transmitted over the LMR network andthis overrides any user inputs or preferences. If the LMR settings donot override the user inputs or preferences, then at 362 a network touse for communication is selected based on the user inputs orpreferences and the corresponding communication portion of the LMR unitis accessed, for example, the LMR communication portion 40 of the LMRunit 22 or the cellular data network communication portion 42 of the LMRunit 22 (all shown in FIG. 2). This also may include using thedetermined operating conditions of the LMR unit to make the selection.

If at 360 a determination is made that the LMR settings override theuser inputs or preferences then at 364 the network to use forcommunication is selected based on the LMR settings. This also mayinclude using the determined operating conditions of the LMR unit tomake the selection. It should be noted that selection of the network touse at either 362 or 364 may result in a new network selected or nochange in the network (i.e., continue using the current network forcommunication). Further, after the selection of the network at either362 or 364, if the network is changed then an indication may be providedat 366, for example, and audible indication (e.g., sound) or visualindication (e.g., LED on LMR unit illuminated or network selectiondisplayed on display).

The method 350 may be performed, for example, periodically or uponcertain events such as a user input, change in operating condition ofthe LMR unit, which may include exceeding a predetermined threshold,etc.

Referring now to FIG. 13 and a method 150 for processing the LMRcontent, at 152 a determination is made as to whether the LMR content isto be communicated using an LMR network. If a determination is made at152 that the LMR content is to be communicated using an LMR network thenat 154 the LMR content is communicated to the LMR network. This mayinclude communicating the LMR content to a base station of the LMRnetwork based on an LMR protocol header provided in combination with theLMR content. Thereafter, the LMR content is encapsulated at 156, forexample, encapsulated in a wrapper defined by the airlink protocol asdescribed herein and routed accordingly at 158. For example, theencapsulated LMR content, which may be configured as a datagram, may berouted within the packet switched LMR infrastructure.

At the destination of the LMR content, the LMR content is processed at160, for example, decapsulated and then an action determined at 162based on the processed data. For example, a determination may be made at162 that an emergency signal is to be transmitted or that the LMRcontent is to be further routed to another base station. Thecorresponding action is then performed at 164, for example, within thepacket switched LMR infrastructure.

If a determination is made at 152 that the LMR content is not going tobe communicated using the LMR network, then the LMR content isencapsulated for communication at 166. For example, in an exemplaryembodiment, the LMR encapsulation module 36 (shown in FIG. 2) implementsthe LMR encapsulation layer 70 (shown in FIG. 8) to encapsulate the LMRcontent in a wrapper, for example, an IP wrapper. The encapsulated LMRcontent is then communicated using a cellular data network at 168. Thismay include routing the encapsulated LMR content in the cellular datanetwork at 170. The LMR content is then communicated to the packetswitched infrastructure at 172, for example, based on the IP addressfrom the IP wrapper.

The LMR content is then processed at a destination, which may includedecapsulating the LMR content and determining an action at 162. Forexample, a determination may be made that an emergency signal is to betransmitted or that the LMR content is to be further routed to anotherbase station. The corresponding action is then performed at 164, forexample, within the packet switched LMR infrastructure.

Thus, various embodiments of the present invention provide forcommunicating LMR content using an LMR network or a non-LMR network, forexample, a cellular data network. If the LMR content is to becommunicated using the cellular data network, the LMR content isencapsulated into a packet switching protocol before transmission. Forexample, and as shown in FIG. 14, an LMR communication system 200generally includes a plurality of cellular data network base stations202 and a plurality of LMR network base stations 204. Each of theplurality of cellular data network base stations 202 and plurality ofLMR network base stations 204 have a corresponding cellular data networkcommunication coverage area 206 and an LMR network communicationcoverage area 208, respectively. The cellular data network communicationcoverage area 206 and LMR network communication coverage area 208 may beoverlapping at some locations. The various embodiments of the inventionas described herein allow an LMR unit 210, for example, an LMR radio ina mobile unit or vehicle, to communicate via either a cellular datanetwork or an LMR network depending on, for example, the location of theLMR unit 210 and the corresponding available coverage area. Moreparticularly, communication towers (not shown) corresponding to each ofthe plurality of cellular data network base stations 202 and each of theplurality of LMR network base stations 204 allow wireless communicationas described herein.

Further, as shown in FIG. 15, a controller 212 within the packetswitched infrastructure 41 may be configured to control communicationsfrom the plurality of cellular data network base stations 202 andplurality of LMR network base stations 204 as described herein. Thecontroller may process a plurality of data packets received from eitherthe LMR network 24 and/or cellular data network 26 to determine anappropriate action or routing procedure for the particular data packetsas described herein.

The various embodiments or components, for example, the LMRcommunication system 20 or controllers therein, or the LMR units orcontrollers therein, may be implemented as part of one or more computersystems, which may be separate from or integrated with the LMRcommunication system 20 or LMR unit, respectively. The computer systemmay include a computer, an input device, a display unit and aninterface, for example, for accessing the Internet. The computer mayinclude a microprocessor. The microprocessor may be connected to acommunication bus. The computer may also include a memory. The memorymay include Random Access Memory (RAM) and Read Only Memory (ROM). Thecomputer system further may include a storage device, which may be ahard disk drive or a removable storage drive such as a floppy diskdrive, optical disk drive, and the like. The storage device may also beother similar means for loading computer programs or other instructionsinto the computer system.

As used herein, the term “computer” may include any processor-based ormicroprocessor-based system including systems using microcontrollers,reduced instruction set circuits (RISC), application specific integratedcircuits (ASICs), logic circuits, and any other circuit or processorcapable of executing the functions described herein. The above examplesare exemplary only, and are thus not intended to limit in any way thedefinition and/or meaning of the term “computer”.

The computer system executes a set of instructions that are stored inone or more storage elements, in order to process input data. Thestorage elements may also store data or other information as desired orneeded. The storage element may be in the form of an information sourceor a physical memory element within the processing machine.

The set of instructions may include various commands that instruct thecomputer as a processing machine to perform specific operations such asthe methods and processes of the various embodiments of the invention.The set of instructions may be in the form of a software program. Thesoftware may be in various forms such as system software or applicationsoftware. Further, the software may be in the form of a collection ofseparate programs, a program module within a larger program or a portionof a program module. The software also may include modular programmingin the form of object-oriented programming. The processing of input databy the processing machine may be in response to user commands, or inresponse to results of previous processing, or in response to a requestmade by another processing machine.

As used herein, the terms “software” and “firmware” are interchangeable,and include any computer program stored in memory for execution by acomputer, including RAM memory, ROM memory, EPROM memory, EEPROM memory,and non-volatile RAM (NVRAM) memory. The above memory types areexemplary only, and are thus not limiting as to the types of memoryusable for storage of a computer program.

It also should be noted that the various embodiments of the presentinvention also may provide different and/or additional functionality.For example, end-to-end encryption may be performed, thereby eliminatingthe use of intervening encryption equipment and the security riskencountered by having such intervening equipment with access toencryption keys. Further, various embodiments of the present inventionmay provide end-to-end digital voice coding, thereby eliminating the useof intervening transcoding equipment and hence the fidelity lossencountered when one digital voice format is converted to anotherformat.

Additionally, the various embodiments of the present invention mayprovide mission critical functions such as, for example, PTT, scanning,priority calls with preemption, emergency alerting and notification,content scanning and tracking, navigation, dispatch and GPS location.The mission critical functions may be implemented in different missioncritical applications, including, but not limited to, public safety,utility industry and public transit industry.

Thus, the various embodiments provide multimode operation that allowsimplementing the same features, functions and user interface,independent of the system (e.g., LMR network or cellular network) onwhich the LMR unit is operating. The various embodiments also allowend-to-end encryption between LMR devices across different systems.Additionally, coding and recoding of the voice content is eliminated,thereby preserving voice quality.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. A land mobile radio (LMR) comprising: an LMR communication portionconfigured to provide communication with an LMR network; and a cellulardata network communication portion configured to provide communicationwith a cellular data network.
 2. An LMR in accordance with claim 1wherein the cellular data network communication portion comprises acellular radio modem.
 3. An LMR in accordance with claim 1 wherein theLMR communication portion is configured to communicate using an LMRprotocol and the cellular data network communication portion isconfigured to communicate using an LMR-over-cellular protocol.
 4. An LMRin accordance with claim 3 wherein the LMR-over-cellular protocolcomprises a packet switching protocol.
 5. An LMR in accordance withclaim 1 further comprising a user interface configured to receive a userinput to select one of the LMR communication portion and cellular datanetwork portion for communication of LMR content.
 6. An LMR inaccordance with claim 1 further comprising a processor configured toautomatically select one of the LMR communication portion and cellulardata network communication portion for communication of LMR content. 7.An LMR in accordance with claim 1 further comprising a processorconfigured to automatically select one of the LMR communication portionand cellular data network portion for communication of LMR content basedon at least one of an operating condition, a user setting and apredetermined setting.
 8. An LMR in accordance with claim 1 furthercomprising a display configured to identify a selected communicationnetwork.
 9. An LMR in accordance with claim 1 further comprising ahousing having the LMR communication portion and cellular data networkcommunication portion therein and configured to provide handheldoperation.
 10. An LMR in accordance with claim 1 further comprising ahousing having the LMR communication portion and cellular data networkcommunication portion therein and configured in a desktop or dashboardoperating configuration.
 11. An LMR in accordance with claim 1 whereinthe processor is configured to encapsulate LMR content using a packetswitching protocol when communicating using the cellular data networkcommunication portion.
 12. An LMR in accordance with claim 1 wherein theprocessor is configured to allow at least one of end-to-end encryptionand end-to-end digital encoding with at least one other LMR unit.
 13. Amultimode terminal device comprising: a land mobile radio; and acellular radio modem.
 14. A multimode terminal device in accordance withclaim 13 wherein the land mobile radio is configured to communicate LMRcontent using an LMR protocol and the cellular data modem is configuredto communicate LMR content using an LMR-over-cellular protocol.
 15. Amultimode terminal device in accordance with claim 14 wherein theLMR-over cellular protocol comprises a packet switching protocol andfurther comprising an LMR encapsulation module configured to encapsulateLMR content using a packet switching protocol when communication usingthe cellular radio modem.
 16. A multimode terminal device in accordancewith claim 13 wherein the land mobile radio is configured to communicateLMR content using one of a Project 25 (TIA 102), an ETSI TETRA airlinkprotocol, an OpenSky M/A-COM proprietary format, a NetworkFirst and anEDACS system proprietary format.
 17. A multimode terminal device inaccordance with claim 13 wherein the cellular radio modem is configuredto communicate LMR content using one of General Packet Radio Service(GPRS), Enhanced Data Rates for GSM Evolution (EDGE), Evolution DataOptimized (EV-DO), Universal Mobile Telephone Service (UMTS) and 802.11system standard.
 18. A multimode terminal device in accordance withclaim 13 further comprising a processor configured to automaticallyselect for communication of LMR content one of the land mobile radio andcellular radio modem based on at least one of an operating condition, auser setting and a predetermined setting.
 19. A multimode terminaldevice in accordance with claim 13 further comprising a user interfaceconfigured to receive a user input to select for communication of LMRcontent one of the land mobile radio and the cellular radio modem.
 20. Amethod of communicating land mobile radio (LMR) content using an LMRdevice, said method comprising: configuring a land mobile radio tocommunicate LMR content using one of an LMR network and a cellular datanetwork, the LMR content encapsulated using a packet switching protocolwhen communicating using the cellular data network.
 21. A land mobileradio (LMR) comprising: a cellular radio modem; and an LMR encapsulationmodule for encapsulating LMR content to communicate via the cellularradio modem.